#include <skier.h>
#include "skibase16.h"

static unsigned char skibase16_decode_char(unsigned char c)
{
    if(c >= '0' && c <= '9') return c - '0';
    if(c >= 'A' && c <= 'Z') return c - 'A' + 10;
    if(c >= 'a' && c <= 'z') return c - 'a' + 10;
    return 0xFF;
}

int skibase16_decode(char *buff, unsigned long size, unsigned char *out)
{
    if(buff == NULL || size == 0) return 0;
    if(size & 1) size--; if(out == NULL) out = (unsigned char *) buff;
    unsigned char c, *base = out;
    for (; size; size -= 2) {
        if((c = skibase16_decode_char(*buff++)) == 0xFF) return 0;
        *out = c << 4;
        if((c = skibase16_decode_char(*buff++)) == 0xFF) return 0;
        *out++ |= c;
    }
    *out = 0;
    return out - base;
}

int skibase16_encode(unsigned char *buff, unsigned long size, char *out)
{
    if(buff == NULL || size == 0 || out == NULL) return 0;
    char *base = out;
    while (size) {
        *out++ = "0123456789ABCDEF"[*buff >> 4];
        *out++ = "0123456789ABCDEF"[*buff & 15];
        size--, buff++;
    }
    *out = 0;
    return out - base;
}